FIG. 1 schematically shows a structure of a reservoir according to the related art. Generally, the reservoir 100′ is provided in a fuel tank 300′ and is basically configured to include: a receiving part 110′ having a fuel sucking pipe 120′ connected thereto and receiving fuel, the fuel sucking pipe 120′ supplying the fuel to an engine 200′; a supplying part 130′ connected to the receiving part 110′ to supply the fuel in the fuel tank 300′ into the receiving part 110′; and a measuring part 140′ measuring an amount of the fuel received in the receiving part 110′. As a reservoir having a more advanced form, there is a reservoir further including a pump actively sucking up the fuel in the receiving part 110′ to transfer the fuel to the engine 200′. However, the reservoir not including the pump will be described below. In the case of the reservoir not including the pump, the fuel is relatively less stably transferred to the engine as compared to the reservoir including the pump. However, since the reservoir not including the pump has a significantly simple structure, a manufacturing cost is cheap, a fault generation rate is significantly reduced, such that a lifespan is long, and maintenance is convenient. Due to these advantages, the reservoir not including the pump has still been mainly used in a diesel vehicle, or the like.
The supplying part 130′ has a form of a jet pump. The number of jet pumps may be one or more according to a form, a structure, and the like, of the fuel tank 300′. The measuring part 140′ generally has a form of a float, which is one of the simplest structures measuring a water level. In addition, although not shown, the reservoir 100′ is also provided with a structure to which a return fuel discharging pipe discharging fuel returned from the engine 300′ into the receiving part 110′ of the reservoir 100′ is connected, in addition the above-mentioned components.
Meanwhile, fuel used in the vehicle is generally divided mainly into diesel and gasoline. Since the gasoline is generally commercialized in a state in which it is appropriately filtered, the gasoline hardly include foreign materials mixed therewith, such that a specific problem is not generated. However, in the case of the diesel, the ratio of the foreign materials mixed is relatively higher as compared to the gasoline. In addition, the diesel is solidified at a more rapid speed as compared to the gasoline, due to characteristics thereof, as a temperature decreases. Further, since the diesel contains relatively more moisture due to characteristics of a production process thereof, the diesel may also include a lump generated due to the freezing of the moisture in the fuel particularly in a low temperature environment.
Generally, the diesel becomes a slush state at a temperature of about −20° C. and is frozen at a temperature of about −24 to −25° C., and bio diesel starts to be frozen at a temperature higher than −24 to −25° C. Therefore, in a diesel vehicle in which the ratio of using the reservoir not including the pump is high, the lump generated due to the freezing of the diesel or the moisture in the diesel as described above is caught in an inlet of the fuel sucking pipe to block the inlet, such that the sucking of the fuel and the transfer of the fuel to the engine are not appropriately performed.
In the case of the reservoir including the pump, a technology of allowing a filter filtering foreign materials to be included in a pump sucking part, or the like, has been disclosed. However, in the case of a number of vehicles using the reservoir not including the pump, it is difficult to remove these foreign materials or solidification materials. In addition, since the reservoir not including the pump is used due to advantages such as a cheap cost, convenience of maintenance, and the like, a scheme of allowing the filter to be included in the reservoir not including the pump (as in the case of the reservoir including the pump) causes an increases in cost and inconvenience of maintenance, such that it does not solve the above-mentioned problem. In addition, the filter is effective to filter the foreign materials. However, in the case in which the diesel becomes a slush state or the lump is generated due to the freezing of the diesel or the moisture in the diesel, these solidification materials cover the filter over a very wide area, such that flow of the fuel may become more difficult due to the filter. Therefore, it is not preferable to use the filter.
Therefore, a structure allowing fuel to be smoothly transferred particularly at a low temperature, that is, at a point of time in which solidification occurs in the fuel in a reservoir not including a pump has been continuously demanded by those skilled in the art.